1. Field of the Invention
The present invention relates to a tillage system used by farmers to till a field in spring prior to planting and in fall after harvesting farm crops; and, more particularly to a tillage system used to produce deep tilled rows and shallow tilled regions therebetween, leaving behind a smooth clean-tilled field that conserves water and soil fertility without excessive soil erosion.
2. Description of the Prior Art
Many patents address issues related to tilling a farm field. Several of the tillage systems are designed to deep-till a field. Such deep-tilling causes top soil loss due to soil erosion. In addition, deep-tilling degrades field fertility more and more each year. Run-off of soil and fertilizer tends to pollute rivers and waterways. Some of the patents restrict deep tilling to spaced rows. These tillage systems practice minimal tillage principles and leave behind compacted soil between deep tilled rows with stocks of weed protruding from the soil resulting in unsightly field after the tillage operation. Besides, the compacted soil between the deep tilled rows encourages water run offs and soil erosion at the deep tilled rows.
U.S. Pat. No. 3,941,193 to Shoemaker discloses a ground tilling apparatus. The tilling apparatus characterized by a regulating drive connection between the towing tractor drive axle and the tiller shaft, the tiller tines having a modified arcuate configuration which provide a pocketed, rather than a furrowed or channeled, tilling depth profile. The tiller shaft drives the tiller in the same direction with the tiller circumferential speed substantially equal to the ground speed of the tractor, whereby said tips generate a curtate cycloidal curve as the tines rotate and the tips pierce the ground by curtate cycloidal movement with the shank portions following in the holes formed by the tips. This tilling apparatus has two sets of tilling tines oriented and turned in opposite directions. The first tine rotational speed is matched to the ground speed so as to remove large clumps of soil and the second set of tines bust the clumps. The device does not till deep along planting rows.
U.S. Pat. No. 4,102,406 to Orthman discloses a ground conditioning device and method of conditioning soil. This device creates water-holding and retaining cavities that are formed in furrows with the cavities being staggered between adjacent rows. An arm spring biased downwardly carries a hub having spikes in planes laterally spaced apart with the spikes around the hub being staggered between the planes. Each spike is concave longitudinally and in transverse cross section and is secured to opposite sides of a disc mounting plate by a pair of clamping elements one of which is integrally connected to the mounting plate. The hiller row unit is used after the row crop is established in a bed prepared by the splitter or shaper equipment that is disclosed in U.S. Pat. Nos. 3,718,103 and 3,870,108. The hiller provides for ridging with an absolute minimum of root pruning with only the soil that is used to build the ridge being disturbed. The device does not deep-till a plurality of parallel rows where seed planting is planned.
U.S. Pat. No. 4,834,189 to Peterson et al. discloses a row crop cultivator. The row crop cultivator is adapted for use in minimum tillage applications. A plurality of ganged cultivating units is mounted on a tool bar adapted to be towed behind a tractor vehicle. Each cultivating unit comprises a frame, which is supported on a pair of spaced-apart gauge wheels. Also mounted on the frame for rotation within the gap between the gauge wheels is a disk-shaped coulter blade, which is configured to cut through crop residue and weed debris as the material being cut is held against the ground surface by the gauge wheels. This arrangement tends to prevent improper cutting known as “hair-pinning”. Trailing directly behind the coulter blade is a middleworker comprising a narrow width shank depending from the frame. The shank has a weld point on its lower leading edge and wing-like share blades flaring rearwardly and outwardly at a predetermined angle from the lower end of the shank. The middleworker design reduces the tendency for slabs of earth to be thrown onto and thereby damaging growing row crops. The row crop cultivator shields the row of plants that are growing in rows with a pair of coulters and the portion between the rows is weeded or disturbed by a horizontal tiller. The row crop cultivator does not deep-till the field at row planting locations.
U.S. Pat. No. 5,623,997 to Rawson et al. discloses a soil zone-builder coulter closer/tiller. The soil manipulation device is provided for closing a groove in soil formed by a soil tiller shank. The device includes a frame connected to a rear portion of the tiller shank and a pair of rotatable coulter blades mounted on the frame for engaging soil behind the tiller shank. The coulter blades are positioned on opposite sides of the groove so as to close the groove in the soil behind the tiller shank. The coulter blades are selectively movable and positionable in directions toward and away from each other so as to vary the distance between the coulter blades. The coulter blades also are selectively movable and positionable in a substantially vertical direction with respect to the frame, so as to permit variation in depth of coulter blade penetration into the soil. The coulter blades have side surfaces, which are selectively movable and positionable from orientations which are substantially in parallel with the groove to orientations which are out of parallel with the groove, so as to variably manipulate soil on opposite sides of the groove. The tiller meant for inserting seeds is followed by two coulters that close the soil groove formed by the tiller. The coulters may be independently positioned to adjust the groove closing process. The device of the '997 patent does not till a field; but rather plants seeds in a previously tilled field and closes the grove formed after setting plant seeds in the groove.
U.S. Pat. No. 7,575,066 to Bauer discloses a zone tillage tool and method. This patented device is marketed as “Soilwarrior”, and detailed by the web page at http://www.soilwarrior.com/soil.php. This zone tillage tool comprises a tool frame connected by a parallel lift linkage to a tool bar. A fall tillage coulter or dual spring tillage coulters can be carried on the tool frame in advance of a pair of containment coulters. The fall tillage coulter tills soil in a zone that is approximately 7 to 9 inches deep while the spring tillage coulters till 2 to 3 inches deep. The tillage tool has a tool bar that mounts a plurality of tools with its own tool frames carrying independently controllable tillage coulter followed by a pair of slanted containment coulters in the direction of movement of the tillage tool. The tillage tool with its plurality of tillage coulter and containment coulters only creates deep tilled grooves in the field at the places where planting will be done. Spaces between these deep grooves are not tilled, and the soil remains undisturbed with all the weeds still in place, creating an unsightly appearance, Moreover, when rain water or irrigation water is applied to the field, all the water runs into the deep grooves, which have only limited volume and ability to absorb water. This causes selective erosion of soil from the deep grooves. The rainwater or irrigation water runs freely on the compacted soil between the deep tilled rows; run-off water rich in fertilizers and top soil pollutes lakes and rivers.
A number of prior art patents disclose coulters of different geometry and harrowing tools. For example, U.S. Pat. No. 369,163 to Clark discloses a disk harrow; U.S. Pat. No. 1,954,783 to Bohmker discloses a disk blade; U.S. Pat. No. 4,538,688 to Szucs et al, discloses fluted coulter blade and U.S. Pat. No. 5,649,602 to Bruce discloses wavy coulter.
There remains a need in the art for a tillage system that deep-tills at the planting rows so that planted seeds grow easily and vigorously. The entire field should not be deep-tilled, since deep-tilling everywhere results in water run-offs that produce soil erosion and fertilizer loss with consequent pollution of rivers and water ways. There is need in the art for a tilling system that clears plant debris, including stocks, sufficiently to leave behind a field with a clean-tilled appearance and minimal soil disturbance between the deep-tilled rows and which provides sufficient water absorption and storage to prevent water run-offs and consequent soil erosion.